Based on the popular, just-cancelled Disney channel series, "Lizzie McGuire," which I have been an unlikely fan of for several months (at 21, I am about ten years past the target demographic), "The Lizzie McGuire Movie" acts as a sort of farewell capper to the show and characters. While transferring the series' lightweight humor and tone, the film makes the grave mistake of turning the proceedings into what could best be described as a far-fetched fantasy. The result is something more dissatisfying and lazily written than expected.

For anyone who has watched the show already knows, Lizzie McGuire (Hilary Duff) is a normal, sweet-natured 14-year-old whose accident-prone ways leave her hanging just outside her school's popularity stratosphere with best friends Gordo (Adam Lamberg) and Miranda (LaLaine, mysteriously absent from the picture and off on a trip to Mexico). As celebration for graduating middle school, Lizzie bids her parents (Hallie Todd, Robert Carradine) and mischievous younger brother, Matt (Jake Thomas), farewell, and sets off with Gordo and the rest of her classmates for a two-week trip to Rome. Lizzie and Gordo are determined to experience a few adventures along the way, but Gordo finds himself on the sidelines, having to cover for Lizzie when she meets Italian pop star Paolo (Yani Gellman), who claims she is a dead ringer for singing partner Isabella. It seems they are contracted to perform together at an upcoming concert at the Coliseum, but with Isabella missing in action, he needs someone to stand in for her. Despite being horrified of public appearances, Lizzie reluctantly agrees, immediately finding herself the center of attention even as she must play the part of someone else—a task she realizes isn't the right thing to do.

Directed by Jim Fall, whose debut was the 1999 gay romantic comedy, "Trick," "The Lizzie McGuire Movie" is as light as a feather and as insignificant as whipped cream, threatening to evaporate even as it continues to play itself out. For a while, it works, thanks in no small part to 15-year-old star-in-the-making Hilary Duff (2003's "Agent Cody Banks"), who is thoroughly delightful and identifiable as the bubbly Lizzie McGuire. Duff commands the screen without even trying, her 1000-watt smile able to brighten even the dimmest of scenes. It also turns out she has quite a good singing voice, performing two catchy pop songs, "What Dreams Are Made Of" and "Why Not," the former one acting as the centerpiece for the concert climax.

On entertainment value alone, "The Lizzie McGuire Movie" works better than the recent Amanda Bynes comedy, "What a Girl Wants," if only because it moves at a quicker pace and is fifteen minutes shorter. It doesn't take too long, however, to come to the disheartening realization that screenwriters Susan Estelle Jansen, Ed Decter, and John J. Strauss have done a slight disservice to the show from which it is based. The dialogue is less witty by a half, and the show's mostly reality-based storylines have been traded in for a bogus daydream fantasy about celebrity treatment, lip-synching, and unexplained dopplegangers. With every other scene dedicated to music montages (an act of desperation to pad any movie's running time out), someone should have realized before they fast-tracked this screenplay into production that it was lacking most of what makes the series so darn endearing and fresh.

Aside from the lovely Duff, Alex Borstein (2002's "Showtime")—a former cast member of "MadTV," best known for her character of Ms. Swan—is very funny as the trip's controlling, egomaniacal chaperone/tour guide Miss Ungermeyer. Adam Lamberg is winning as Lizzie's curly-haired best bud, Gordo, who secretly hopes their friendship could be more than a platonic one. And Jake Thomas (2001's "A.I.: Artificial Intelligence") is appropriately bratty and cute as Lizzie's little brother, Matt. As her supportive parents, Hallie Todd and Robert Carradine (2001's "Max Keeble's Big Move") aren't around long enough to develop their characters much more beyond what has already been played out on the small screen.

"The Lizzie McGuire Movie" is undemanding entertainment, something that will delight young girls even as it sends a misguided and unbelievable message about what it takes to be happy and feel like you belong. The ending is also too rushed to be satisfying, heading into the end credits before it has gotten around to concluding some of the subplots and characters. As much as I like Hilary Duff and "Lizzie McGuire," they both deserved better than this underwhelming big screen outing.